Production Technology of Maize

Maize is a crucial crop cultivated in both spring and kharif seasons. It plays an essential role in fulfilling food security needs and providing raw materials for various industries. The area under maize cultivation has been increasing, and improved hybrid varieties, along with better agricultural practices, have significantly enhanced yield per hectare.

The primary reasons behind increasing maize production include the use of modern agricultural technology, quality seeds, better irrigation methods, and effective pest control strategies. The government and agricultural research institutions are working together to introduce high-yielding and disease-resistant maize varieties to maximize production. Farmers are encouraged to adopt precision farming techniques and follow expert recommendations to improve yield and quality.

Note

Proper soil preparation, balanced fertilization, and timely sowing are key to achieving high maize yields.

Crop Rotation and Maize Cultivation

Maize, due to its short growth duration, is a versatile crop that can be easily integrated into various crop rotation systems. This document outlines suitable crop rotations for irrigated areas, focusing on both one-year and two-year cycles.

Importance of Crop Rotation

Rotating maize fields helps in minimizing the impact of diseases and harmful insects, leading to healthier and more productive crops.

One-Year Crop Rotation

Here are some recommended one-year crop rotation patterns:

  • Autumn Maize - Wheat/Potato - Spring Maize
  • Autumn Maize - Berseem - Paddy (Coarse Varieties) - Potato - Spring Maize
  • Autumn Maize - Potato - Spring Maize

Two-Year Crop Rotation

For a two-year cycle, consider these rotations:

  • Autumn Maize - Wheat - Autumn Maize - Berseem
  • Autumn Maize - Wheat - Cotton - Berseem

Spring Maize Crop

Growth Characteristics

The spring maize crop experiences lower temperatures during its initial growth phases, followed by longer days and abundant sunlight. This extended growth period contributes to higher yields.

Yield Advantage

Spring maize typically yields 25-30% more than autumn maize due to longer growth periods and ample sunlight during later stages.

Varieties

Maize Varieties Developed by Research Institute, Sahiwal

General Maize Varieties (Synthetic Varieties)

The following table lists the recommended general (synthetic) maize varieties:

Serial No. Variety Name Season Approval Year Grain Color Yield Potential (Maunds/Acre)

Maturity Period in Days

(Spring)

Maturity Period in Days

(Autumn)
1 Malika 2016 2016 2016 Yellow 86 115 100
2 Gohar 19 2019 2019 White 81 105-110 95-100
3 Sahiwal Gold 2019 2019 Yellow 91 110-115 100-105
4 Summit Pak 2019 2019 White 71 90-100 85-90
5 Pop-1 2019 2019 Yellow 55 90-95 90-95
6 Sweet-1 2019 2019 Yellow 44 90-95 90-95
Note
  • General maize varieties are more suitable for cultivation in rainfed areas where there is no adequate irrigation system.
  • These varieties are also very suitable for green fodder.

Characteristics of Hybrid Maize Varieties

Hybrid maize varieties are known for their high yield potential. They are produced by crossing two distinct and genetically pure inbred lines, resulting in uniform growth. These varieties have a higher number of grains per cob, and the grains are thicker and heavier, contributing to their increased yield. They also possess medium height, strong stems, and roots, making them responsive to higher fertilizer applications and resistant to lodging.

Seed Rate

  • Seed Rate per Acre: 8 to 10 kilograms
Important

Ensure that the seeds are clean, healthy, pure, and have a germination rate exceeding 90 percent.

Seed Treatment

To safeguard the crop, it is essential to treat the seeds with one of the following pesticides before sowing:

Pesticide Name Usage Rate
Azoxystrobin + Clothianidin + Fludioxonil 72% WS 9 grams per kilogram of seed
Imidacloprid + Tebuconazole 372.5% 10 milliliters per kilogram of seed
Azoxystrobin + Clothianidin 62.5% 9 grams per kilogram of seed
Thiamethoxam 350 FS 10 milliliters per kilogram of seed

Importance of Seed Treatment

Seed treatment is crucial for:

  • Protecting seeds from early insect attacks, particularly sap-sucking insects like shoot flies.
  • Preventing the onset of diseases during the initial growth stages of the crop.
  • Ensuring healthy and vigorous seedling establishment.

Sowing Time

Spring Crop Autumn Crop
Late January to 28th February 15th July to 15th August

Important Factors for Sowing Time

  • Climate Adaptation: Adjust maize sowing time as needed to adapt to climatic changes.
  • Green Cob Production: For harvesting green cobs, autumn maize can be sown until the end of August.
  • Rainfed Areas (Attock, Jhelum, Rawalpindi, Chakwal, Gujrat): Align maize sowing with the onset of the monsoon season.
  • Rainfed Areas (Punjab): Select and sow early maize varieties based on their earliness, considering the next crop in the rotation.

Suitable Land

  • Ideal Soil: Loam, heavy loam, and deep fertile soils with good organic matter and water absorption capacity are ideal for maize cultivation.
  • Unsuitable Soil: Avoid sandy, saline, and alkaline soils as they are not suitable for maize.

Importance of Land Preparation

For maize seeds to germinate successfully, the field must provide:

  • Adequate moisture
  • Suitable temperature
  • Friable soil

Steps for Land Preparation

  1. Deep Plowing: If the soil has hard layers, plow deeply every two to three years.
  2. Land Leveling: Level the field to ensure uniform water distribution. It is recommended to use a laser land leveler for precise leveling.
  3. Plowing and Harrowing: Plow and harrow the field three to four times for better soil preparation.
  4. Residue Management: If there are stubbles or clods from the previous crop, use a rotavator to break them into fine pieces before further cultivation.

Maize Cultivation Methods

Maize cultivation can be successfully achieved using various methods. This document focuses on ridge planting, a common technique in irrigated areas.

1. Ridge Planting

Ridge planting is a preferred method for maize cultivation in irrigated regions.

Procedure

  1. Ridge Formation: Create ridges running east to west, spaced two and a quarter to two and a half feet apart.
  2. Irrigation: Apply light irrigation to the field.
  3. Planting: Immediately after irrigation, plant a single seed on the slope of the ridge, slightly above the water level.
  4. Orientation:
    • Spring Planting: Plant on the south side of the ridge to benefit from sunlight throughout the day, promoting faster germination.
    • Autumn Planting: Plant on the north side of the ridge to retain moisture for a longer period, ensuring better germination.
  5. Spacing
  • Spring Maize:
    • Hybrid Varieties: 6 inches spacing
    • General Varieties: 7 to 8 inches spacing
  • Autumn Maize:
    • Hybrid Varieties: 7 inches spacing
    • General Varieties: 8 to 9 inches spacing

Maize planting on ridges

2. Bed Planting

In irrigated areas, maize is also planted on beds. This method involves planting maize on beds spaced three and a half feet apart. The top of these beds is approximately two and a half feet wide, and seeds are planted on both sides of the bed’s center.

  • Spring Maize:
    • Hybrid varieties: 8 to 9 inches spacing
    • General varieties: 10 to 11 inches spacing
  • Autumn Maize:
    • Hybrid varieties: 10 inches spacing
    • General varieties: 11 to 12 inches spacing

Maize Bed Planting

3. Row Planting

In rainfed areas, maize should be planted using a drill, planter, or pour at a spacing of two and a half feet. Once the crop reaches 4 to 6 inches in height, thin out weaker and diseased plants.

  • Early Maturing Varieties: Maintain a plant-to-plant spacing of 6 to 7 inches.
  • Late Maturing Varieties: Maintain a plant-to-plant spacing of 7 to 8 inches and remove excess plants.

4. Planting with Maize Planter

Using an automatic maize planter is highly beneficial for timely and effective maize planting. This method ensures better and uniform germination and also reduces labor and planting costs.

Figure 1: Maize Planter

Sweet Corn and Popcorn Maize

Plant Spacing

For both sweet corn and popcorn:

  • Spring Planting: Maintain a plant-to-plant spacing of 8 inches.
  • Autumn Planting: Maintain a plant-to-plant spacing of 9 inches.

Plant Population on Ridges

The following table shows the plant population per acre obtained by planting on ridges with 2.25 feet and 2.5 feet spacing.

Note

Remember that each ridge will have one row of plants.

Serial No. Plant Spacing Plant Population on 2.25 Feet Spaced Ridges Plant Population on 2.5 Feet Spaced Ridges
1 6 inches 38720 34848
2 7 inches 33189 29870
3 8 inches 29040 26136
4 9 inches 25813 23232
5 10 inches 23232 19913

Plant Population on Beds

The following table shows the plant population per acre obtained by planting on beds spaced at 3 feet, 3.5 feet, and 4 feet, with two rows of plants per bed.

Note

Remember that each bed will have two rows of plants.

Serial No. Plant Spacing Plant Population on 3 Feet Spaced Beds Plant Population on 3.5 Feet Spaced Beds Plant Population on 4 Feet Spaced Beds
3 8 inches 43560 37337 32670
4 9 inches 38720 33189 29040
5 10 inches 34848 29870 26136

Seed Depth

Proper seed depth is crucial for optimal maize germination.

  • Loam and Heavy Loam Soils: Plant maize seeds 1.5 to 2 inches deep.
  • Sandy Soils: Plant maize seeds at least 2 inches deep.
Note

Avoid transplanting seedlings to fill gaps in the maize crop. Transplanted seedlings do not grow as well as directly sown plants and negatively impact yield.

Irrigation

Maize irrigation requirements vary by season and planting method.

  • Spring Maize (Ridges): 12 to 14 irrigations typically needed.
  • Autumn Maize: 10 to 12 irrigations typically needed.

Irrigation Guidelines

  • First Irrigation Timing:
    • Leveled fields: 10 to 12 days after germination.
    • Ridges and furrows: Maintain soil moisture until germination.
    • Seasonal maize: Irrigate on the 4th day after sowing to aid germination.
  • Critical Growth Stages: Ensure adequate moisture during flowering, pollination, and the milky stage.
  • Weather Considerations:
    • Reduce irrigation intervals during extreme heat.
    • Increase irrigation intervals during cooler temperatures.
  • Drainage: Promptly remove excess water after heavy rainfall.
  • Weather Forecasting: Check weather forecasts before irrigating.

Weed Control in Maize

Weeds can reduce maize yield by 30 to 50 percent in some cases.

Weed Control Methods

  • Manual Weeding: Suitable for small-scale cultivation.
  • Chemical Weed Control: Use pre-emergence herbicides for effective control.

Pre-Emergence Herbicide Application

The following table provides information on a recommended pre-emergence herbicide:

Serial No. Herbicide Weeds Controlled Application Rate Per Acre Application Time
1 Atrazine + S-Metolachlor 720 SC For all types of weeds 800 ml Within 24 to 48 hours of sowing

Post-Emergence Herbicide Application

The following table details the recommended post-emergence herbicides:

Serial No. Herbicide Weeds Controlled Application Rate Per Acre Application Time
1 Mesotrione + Atrazine 48 SC Barnyard grass and broadleaf weeds 650 ml When all weeds have emerged
2 Halosulfuron-methyl 75 WDG Nut grass 20 grams At nut grass emergence
3 Isoxaflutole 19.07% Grass and broadleaf weeds 132 ml From emergence to the three-leaf stage
Important

If nut grass control is insufficient, a second application of Mesotrione + Atrazine 48 SC at 650 ml per acre can be made after a 15 to 20 day interval.

Determining Fertilizer Needs

Fertilizer requirements are determined by:

  • Soil fertility
  • Salinity
  • Soil type
  • Water quality
  • Cropping intensity
  • Previous crop
Recommendation

Perform a soil laboratory analysis to accurately determine fertilizer needs.

Fertilizer Recommendations for Hybrid Maize

The following table provides fertilizer recommendations for hybrid maize varieties based on soil type:

Soil Type N (kg/ acre) P (kg/ acre) K (kg/ acre) Application Time 5 to 6 Leaf Stage 8 to 10 Leaf Stage 1 week prior to flowering

Weak Soil

(Organic matter < 0.87%, Phosphorus < 7 ppm, Potash < 80 ppm)

 119 69 50

3 bags DAP + 2 bags SOP + 1/4 bag Urea

OR

7.5 bags SSP (18%) + 2 bags SOP + 1.5 bags Urea

 1.25 bags Urea 1.25 bags Urea 1.25 bags Urea

Medium Soil

(Organic matter 0.87-1.29%, Phosphorus 7-14 ppm, Potash 80-180 ppm)

 92 58 37

2.5 bags DAP + 1.5 bags SOP

OR

6.5 bags SSP + 1.5 bags SOP + 1 bag Urea

 1 bag Urea 0.75 bag Urea 0.75 bag Urea

Fertile Soil

(Organic matter > 1.29%, Phosphorus > 14 ppm, Potash > 180 ppm)

 75 46 25

2 bags DAP + 1 bag SOP

OR

5 bags SSP + 1 bag SOP + 0.75 bag Urea

 1 bag Urea 0.75 bag Urea 0.75 bag Urea

Abbreviations

  • DAP: Diammonium Phosphate
  • SOP: Sulfate of Potash
  • SSP: Single Super Phosphate

Fertilizer Recommendations for Common Maize Varieties (Irrigated Areas)

The following table provides fertilizer recommendations for general maize varieties based on soil type:

Soil Type N (kg/ acre) P (kg/ acre) K (kg/ acre) Application Time 5 to 6 Leaf Stage 8 to 10 Leaf Stage 15 days prior to flowering

Weak Soil

(Organic matter < 0.87%, Phosphorus < 7 ppm, Potash < 80 ppm)

 92 58 37

2.5 bag DAP + 1.5 bag SOP

OR

6.5 bag SSP + 1.5 bag SOP + 1 bag Urea

 1 bag Urea 1 bag Urea 1 bag Urea

Medium Soil

(Organic matter 0.87-1.29%, Phosphorus 7-14 ppm, Potash 80-180 ppm)

 80 46 37

2 bag DAP + 1.5 bag SOP

OR

5 bag SSP + 1.5 bag SOP + 0.75 bag Urea

 1 bag Urea 1 bag Urea 0.75 bag Urea

Fertile Soil

(Organic matter > 1.29%, Phosphorus > 14 ppm, Potash > 180 ppm)

 70 35 25

1.5 bag DAP+ 1 bag SOP

OR

4 bag SSP + 1 bag SOP + 0.5 bag Urea

 1 bag Urea 0.75 bag Urea 0.75 bag Urea

Fertilizer Recommendations for Common Maize Varieties (Rainfed Areas)

Region N (kg/ acre) P (kg/ acre) K (kg/ acre) Application Time
Low Rainfall Areas 34 23 12

1 bag DAP + 2 bag Ammonium Nitrate + 0.5 bag SOP

OR

1 bag DAP + 1 bag Urea + 0.5 bag SOP

OR

2.5 bag SSP + 1.5 bag Urea + 0.5 bag SOP
High Rainfall Areas 46 34 25

1.5 bag DAP + 2.5 bag Ammonium Nitrate + 1 bag SOP

OR

1.5 bag DAP + 1.5 bag Urea + 1 bag SOP

OR

4 bag SSP + 2 bag Urea + 1 bag SOP

Fertilizer Application Guidelines

  • Hybrid Varieties: Tailor fertilizer application to the specific needs of the hybrid variety.
  • Farmyard Manure: Apply 3-4 trolleys of well-rotted farmyard manure per acre one month before sowing, if available.
  • Pre-Ridge Fertilization: Apply fertilizers intended for sowing before making ridges.
  • Rainfed Areas: Apply the full recommended fertilizer dose at sowing.
  • Planter Application: Use a maize planter to apply fertilizers at sowing if planting with a planter.
  • Potash Timing: Apply potash fertilizer as recommended, not at flowering, as the plant absorbs 70-80% of its requirement before flowering. If missed at sowing, apply later.
  • Sweet Corn and Popcorn: Follow fertilizer rates for general varieties. Close placement of fertilizer to the seed (at a safe distance) improves efficiency and yield.

Zinc and Boron Application

  • Zinc: Apply 10 kg of 21% zinc sulfate or 6 kg of 33% zinc sulfate per acre.
  • Boron: Apply 3 kg of borax (11% boron) per acre.
  • Alternatives: Use any other suitable zinc and boron compound.

Nutrient Deficiency Symptoms in Maize

Nitrogen Deficiency

  • Growth Inhibition: Plant growth is stunted.
  • Leaf Yellowing: Leaves begin to turn yellow, starting with older leaves.
  • Progression: Yellowing starts at the leaf tip and spreads towards the base.
  • Severe Deficiency: Leaves turn brown.

Phosphorus Deficiency

  • Growth Stunting: Plant growth is significantly reduced.
  • Weak Root System: Root development is poor.
  • Leaf Discoloration: Leaf tips turn purplish.
  • Leaf Appearance: Leaves appear dark green.

Potassium Deficiency

  • Initial Symptoms: White spots appear on the leaves.
  • Progression: White spots turn brown.

Important Diseases of Maize and Their Control

Seed and Seedling Diseases

Symptoms

  • Seeds fail to emerge after germination.
  • Seedlings (3-9 inches) wither and die.

Cause

  • Various soil-borne fungi.

Control

  • Treat seeds with recommended fungicide before sowing.

Stalk Rot

Symptoms

  • Rotting starts from the second node from the bottom.
  • Specific odor from affected area.
  • Leaves turn yellow and dry out.
  • Plants rot and fall from the affected node.
  • Cobs hang downwards, grains are small and shriveled.

Causes

  • Erwinia chrysanthemi
  • Macrophomina phaseolina
  • Cephalosporium maydis

Control

  • Cultivate resistant varieties.
  • Maintain balanced soil fertility (especially potassium).
  • Avoid excessive nitrogen fertilizers.
  • Practice crop rotation and avoid planting maize in affected fields for a few years.
  • Treat seeds with fungicide.
  • Dispose of crop residues promptly.
  • Maintain recommended plant spacing.
  • Irrigate as needed and ensure proper drainage.
  • Remove and destroy infected plants.

Smut of Maize

Maize smut is caused by Ustilago maydis, a dangerous fungal disease in northern regions.

Symptoms

  • White or blackish galls on affected plants.
  • Galls on male parts, leaves, and buds.
  • Ruptured galls release black spore powder.
  • Cob galls prevent grain development.

Control

  • Plant resistant varieties.
  • Avoid planting maize in affected fields for several years.
  • Remove and destroy plant debris.
  • Treat seeds with fungicide.

Leaf Blight of Maize

Caused by Helminthosporium turcicum and Helminthosporium maydis, reducing yield and fodder quality.

Symptoms

  • Brown and whitish spots on leaves, up to 6 inches long.

Control

  • Destroy previous crop residue.
  • Plant resistant varieties.
  • Spray recommended fungicide.

Ear and Grain Rot of Maize

Caused by various fungi, including Diplodia maydis, Fusarium sp., Aspergillus sp., Nigrospora oryzae, and Penicillium sp., reducing yield and quality.

Symptoms

  • Rotting cobs, affected by rainfall and insects.

Control

  • Avoid weak-stemmed varieties.
  • Plant resistant varieties.
  • Maintain balanced soil fertility.
  • Control cob-boring insects.
  • Destroy plant debris after harvest.

Insect Pests and Control

Sr. # Insect Name Identification Damage Control Method
1 Termite This insect resembles an ant and is light yellow or brown in color. It is a social insect found almost everywhere, with a higher prevalence in rainfed and sandy areas. This insect primarily attacks the underground stems and roots of plants. Affected plants wither and can be easily pulled out. In severe infestations, plants fall to the ground. Apply Fipronil 5 SC at 1 liter per acre at the time of pre-sowing irrigation or at the start of an attack. In areas where termite presence is confirmed, mix Ferrol 80 WG at 60 grams per acre into the soil during land preparation. Avoid using raw farmyard manure.
2 Shoot Fly

Only the larvae of this fly damage the crop. The larvae are initially white and later become light yellow in color. Their lifespan is approximately 12 days. The adult fly resembles a common housefly.

Sweet corn is relatively more susceptible to the attack of the maize seedling fly, so pay special attention to its control.

 Its attack lasts for 20 to 30 days. The larvae enter the young shoots and eat the soft tissue, causing the shoots to dry out. The attack of maize seedling fly is more common in spring maize. The leaves of the plant become entangled and remain small.

Treat seeds with one of the following pesticides to protect the crop for the first 40 days:

  • Clothianidin + Azoxystrobin 62.5% WS: 9 grams/kg seed

  • Imidacloprid + Tebuconazole 37.25 FS: 10 ml/kg seed

  • Thiamethoxam 70 WS: 3 grams/kg seed

  • Imidacloprid 70 WS: 5 grams/kg seed

  • Thiamethoxam 350 FS: 10 ml/kg seed

If an attack occurs, spray either:

  • Emamectin Benzoate 1.9 EC: 200 ml/acre

  • Bifenthrin 10 EC: 250 ml/acre

    Apply the first spray after complete emergence, and a second spray after 8 to 10 days.
3 Maize Stem Borer The moth is yellowish-brown in color. The forewings are khaki-colored. And there’s a double line of black spots on the outer edges. The hind wings of the male are smoky in color. The female has a tuft of hair on the posterior part of her abdomen. While the male’s abdomen lacks a tuft of hair. Larvae attack all parts of the plant except the roots. They bore into the central whorl of the growing crop, making holes, which causes the whorl to dry out. These larvae also attack leaves and sometimes the cob. The attack of grubs on seasonal maize is more common than on spring maize. The stem borer attacks sweet corn relatively more. Therefore, pay special attention to its control. Its attack continues from germination to crop maturity.

After harvesting the crop, remove and destroy the stubble from the field.

Apply 20 Trichogramma cards per acre at the beginning of the crop and replace them every 10 to 15 days until pollen shedding. As a preventive measure, use one of the following pesticides:

  • Chlorantraniliprole 0.4% G at 4 kilograms per acre

  • Fipronil 0.3% G at 8 kilograms per acre

  • Emamectin Benzoate + Fipronil 0.35 G at 8 kilograms per acre

  • Chlorantraniliprole + Thiamethoxam 0.6% GR at 4 kilograms per acre

Apply these to the whorl of the plant and repeat as needed.
4 Jassid
  • This agile insect moves quickly from one place to another.
  • Its color is greenish.
  • It remains active throughout the year.
 Both adults and nymphs suck sap and damage the plant, which causes white spots to appear on the leaves. This insect’s attack is more common on spring maize. In case of severe attack, the leaves dry out. Its attack can become severe at favorable temperatures.

In case of an attack on the crop, use any recommended pesticide.

  • Thiamethoxam 25 WG at 24 grams per acre

    OR

  • Carbosulfan 20 EC at 500 milliliters per acre

    OR

  • Imidacloprid 200 SL at 200 milliliters per acre
5 Aphid This insect is very small and deep green in color. It appears as a cluster on plant leaves, especially on the tips of leaves. Due to the sap excreted from the body of this insect, black mold develops on the leaves, which severely affects the process of food production by the leaves. In addition, it damages the pollen grains, which reduces the ability of grains to form in the cobs and severely affects the yield.

In case of an attack on the crop, use any recommended pesticide.

  • Acetamiprid 20 SP at 125 grams per acre
  • Carbosulfan 20 EC at 250 milliliters per acre
  • Imidacloprid 200 SL at 200-250 milliliters per acre
  • Acephate 97% DF at 250 grams per acre (spray)
6 American Cob Borer The larvae are initially dark brown and later change into various colors. Therefore, identification based solely on color can be misleading. The female moth lays eggs on the silk and tassels. Initially, the tiny larvae eat the pollen from the silk and male flowers. The larvae attack when the tassel and silk emerge. The larvae cut the silk and enter the cob, damaging the grains.

Spray any recommended pesticide in case of an attack.

  • Spinetoram 120 SC at 100 ml per acre
  • Chlorantraniliprole 20 SC at 50 ml per acre
  • Flubendiamide 480 SC at 50 ml per acre
  • Spinosad 240 EC at 40 ml per acre
7 Armyworm The larvae are initially white and later become dark green. There are prominent stripes running lengthwise on both sides of the body. There are black spots above the lines on each segment of the body. The female lays eggs in clusters under leaves and sometimes on top of leaves. The larvae start eating the leaves from the lower surface in groups and not only make holes in the leaves, but also leave behind a thin membrane of the leaf. In case of a severe attack, they eat the entire leaves, and the crop is left bare. Initially, the attack of this larva occurs in patches. The large larvae also eat the silk emerging from the cobs and the soft grains emerging from the husk, which stops the grain formation process.

Spray any recommended pesticide in case of an attack.

  • Chlorantraniliprole 20 SC at 50 ml per acre
  • Indoxacarb 150 SC at 175 ml per acre
  • Flubendiamide 480 SC at 50 ml per acre
  • “Emamectin 1.9 EC at 200 ml per acre”
  • Lufenuron 5% EC at 200 ml per acre
  • Methoxyfenozide 120 SC at 200 ml per acre
8 Mite The adult mite is light greenish-red. It has eight legs. The female lays semi-transparent, pearl-colored eggs on the underside of leaves, which later turn pale green. The adult has two black spots on its body. The young have six legs, but later develop eight legs. The young hatch from the eggs and suck the sap from the leaves. Then nymphs and adult mites also damage the plant by sucking sap. They can be seen by shaking them onto white paper. They lay eggs and spin a fine web of threads over them. Its attack is severe in hot and dry weather during grain formation. Leaves scorch and become discolored. Marks and streaks appear on the leaves. The color of the leaves turns brownish-yellow and the leaves dry out. Up to 40% loss is possible.
  • Keep the fields free of weeds throughout the year.
  • Destroy crop stubble and use a rotavator on fallow land.
  • Keep ditches and embankments free of weeds.
  • Keep the fields moist, do not let them dry out.
  • Spray as advised by agricultural experts in case of an attack.
Note

Never cultivate maize on sandy soil.

Harvesting

Harvest maize when:

  • Inner husks are dry.
  • Grains are shiny and hard.
  • Fingernail cannot pierce grains.
  • Black layer on grain tips.
  • Grain moisture is 30-35%.
Important

Harvesting too early reduces yield and seed viability. Delaying harvest leads to losses from lodging, birds, and fungal contamination (aflatoxin).

Drying Cobs and Separating Grains

  1. Remove husks.
  2. Spread cobs on platforms.
  3. Turn cobs daily for uniform drying.
  4. Cover with tarpaulin if rain is expected.
  5. Grains separate easily when rubbed together.
  6. Grains break with a crack when bitten (15% moisture).
  7. Use a thresher to separate grains.
  8. Store grains below 10% moisture.

Storing Grains

  1. Clean storage area and spray pesticide.
  2. Close doors and windows for 4 hours.
  3. Store maize as cobs or grains.
  4. Separate new grain from old.
  5. Label storage for intended use.
  6. Use 30-35 aluminum phosphide tablets per 1000 cubic feet (monsoon).
  7. Keep storage closed for one week.

Protecting Grains from Aflatoxin

  1. Harvest at 30% moisture or less.
  2. Dry cobs quickly.
  3. Avoid drying on bare ground.
  4. Protect from rain and moisture.
  5. Store below 10% moisture.
  6. Clean grains from debris.

Hermetic Bags and Cocoons

Use hermetic storage for long-term protection without fumigation.

Impacts of Climate Change

  • Heat Stress: Severe heat during pollination in spring crops is particularly detrimental.

Mitigation Strategies

  • Optimal Sowing Time:
    • Sow maize at the recommended time.
    • In southern Punjab, delay autumn maize planting until after July 25th, based on weather conditions.
  • Variety Selection:
    • Plant heat-resistant varieties in spring.
    • Diversify varieties planted across the field.
  • Irrigation Management:
    • Irrigate according to crop needs to minimize heat wave effects during pollination.
  • Best Practices:
    • Follow recommended production technologies.
    • Prioritize plant protection.
  • Weather Awareness:
    • Stay informed about weather forecasts before cultivation activities.
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